This application is a competitive renewal for an Independent Scientist Award. The candidate, Barbara C. Leigh, Ph.D., MPH, a Senior Research Scientist at the Alcohol and Drug Abuse Institute at the University of Washington, proposes to continue her program of research on substance use and risk behavior. The major goal for the next award period is to explore different methodological approaches to examining substance use and risky sexual behavior. The research program includes a meta-analysis of existing studies on the relationship of substance use to risky sexual behavior and a study that uses a daily event data collection methodology to investigate the nature of relationships between substance use and risky sexual behavior. Plans for career enhancement include further training in epidemiology and biostatistics and collaboration with colleagues in public health disciplines. The continuation of this award would provide Dr. Leigh with stable funding and relieve her from reliance on short-term mechanisms of support.